Photographic objective



April 22, 1958 J. BERGER ET AL PHOTOGRAPHIC OBJECTIVE Filed Feb. 13. 1956 PHOTOGRAPHIC OBJECTIVE Johannes Berger, Heidenheim (Brenz), and Guenther Lange, Konigsbronn, Germany, assignors to Carl Zeiss, Heidenheim (Brenz), Germany Application February 13, 1956, Serial No. 565,285

Claims priority, application Germany February 15, 1955 4 Claims. (CI. 88-57) The invention concerns photographic objectives for taking or reproduction consisting of six lenses, of which the first and the second are collective lenses, the third and fourth are dispersive lenses, and the fifth and sixth are collective lenses again, wherein the second and the third lenses are cemented together and wherein furthermore all surfaces whose radius of curvature is numerically smaller than the focal length turn their concave sides towards the diaphragm standing between the third and fourth lenses.

The investigations forming the basis of the invention have shown that a good compromise may be obtained between the aberrations of the axial bundle which determine the image quality on the one hand, and those of the oblique bundles on the other hand, if the following conditions according to the invention are simultaneously fulfilled.

0.50-f D, 0.60-f 1.20-F, D, 1.65-7',

=the focal length of the objective Z=the arithmetical mean of the absolute amounts of the radii of the two surfaces r and r,

D,=the separation of the apices of these two surfaces "=the arithmetical mean of the absolute amounts of the 2 radii of thesurfaces bordering upon the diaphragm Space (IF. 5'; I GI) D =the length of the diaphragm space=d L=the overall length of the objective=the separation of the apices of the two external surfaces d =the airspace between the fourth and the fifth lenses d =the axial thickness of the second lens L d =the axial thickness of the third lens L d =the axial thickness of the fourth lens L d =the axial thickness of the fifth lens L By the combination of these characteristics it is rendered possible according to the invention with objectives of great light-gathering power of a relative aperture of 1:2 to keep all aberrations relatively small especially to combine good central correction simultaneously with good correction of the oblique bundles.

In the illustration attached the schematic design of an objective according to the present invention is represented. In the tables given .in the following numerical values are given for three objectives according to the invention. For these three examples one illustration only is shown since these examples are differentiated as far as the lens scheme is concerned only by the type of the cemented surface between the second and third lenses. In the case of embodiment I particularly the said cemented surface turns its concave side towards the first lens while in the embodiments II and III this cemented surface is a plane surface.

In the figure of the drawing and in the following embodiments there are designated By L L the lenses,

By r r theradii,

By d d the thicknesses and the air spaces between the individual members.

By n the refractive indices, and by v the Abbe numbers.

The values are referred to a focal length of f=l. All embodiments have the aperture ratio 1:2 and an angle of field of approximately 27 on each side of the optical axis.

Embodiment 1 Embodiment 11 [Back focal length a=+0.6836 f] Thlclmesses Lenses Radil and 114 v Separations r =+0.577316 L d =0.0677S 1. 74400 44. 9

d2=0.0031l r =+0.391438 Ln da=0.10821 1. 66672 48. 4

I Q Lm d4=0.01710 1. 62536 35. 6

d=0.28451 n= 0.293543 L v lia=0.031U9 1. 74000 28. 2

d1=0.00994 fg= -2.07811 Lv dg=0.08084 1. 74400 44. 9

d0=0.00311 rm=+10.8747 Lvr I110 =0.08396 1. 74400 44. 9

Embodiment III [Back focal length a =+0.6883X/] Thlcknesses Lenses Radll an 11. v

Separations T1=-P0576526 L1 d1=0.06966 1. 74400 44. 9

d1=0.00l99 r;=+0.393732 L11 da=0.10931 1. 66672 48. 4

f: G L111 d4=0.01590 1. 62536 35. 6

d5=0.27726 r -0.293l43 L v d =0.01988 1. 72825 28. 3

d1=0.00596 Tg= 2.13581 Lv da=0.09600 1. 74400 44. 9

dt=0.01193 f 0=+21.6682 Lvr dm=0.07155 1.74400 44. 9

We claim:

1. A photographic objective for taking or for reproduction consisting of six lenses of which the first and the second are collective lenses, the third and fourth are dispersive lenses and the fifth and sixth are collective lenses again wherein the second and the third lenses are cemented together and wherein furthermore all surfaces whose radius is numerically smaller than the focal length turn their concave sides towards the diphragm standing 4 between the third and m legg characterized in that the o owing con tions are simultaneously fulfilled:

1.80-F, D, 2.20-F 0.90-r [n| 1.20-r 0.002-f d1 0.022- 0.08-f d +d 0.20-f 0.08-f d0+d +d 0.20f 0.24-f r5 0.28-f 0.26f lr0| 0.32-f 0.23-f D,D, 0.28-f wherein the symbols have the significance listed in the following:

f=the focal length of the objective r ,=the arithmetical mean of the absolute amounts of the radii of the two surfaces r and r D,=the separation of the apices of these two surfaces =the arithmetical mean of the absolute amounts of the radii of the surfaces bordering upon the diaphragm space D =the length of the diaphragm space L=the overall length of the objective=the separation of the apices of the two external surfaces d =the air space between the fourth and fifth lenses d =the axial thickness of the second lens L d =the axial thickness of the third lens L d =the axial thickness of the fourth lens L d =the axial thickness of the fifth lens L 2. A photographic objective according to claim 1 characterized in that the individual powers of the refracting surfaces (An/r) differ by a maximum of :O.5/f each and the distances (d) of the individual surface apices differ by a maximum of 10.05% each from the values taken from the following numerical example:

Lenses Radli Thtcknesses and mi 0 A n/r Separations n= 0.510504- +1.290537 L1 I 40-00000 1.14400 44. 9 If n=+1.26403-j 0.593287/I +0 300002 daommj +11o0a0su "I 4 L d1=0.10680-f 1. 00012 42. 4

n= 9.54018-f +0.004s03 1 L111 dc-(LOIEIZJ 1. 02004 as. a

r -+0.263129-j -2.a00411 a.-0.2s22sn--0.288938-I 2.563768/j Lm. d4=0.02016-! 1.14011 21.1

r1= 2.76739-f +0.267678/f d7=0.00605f n- 4.105234 -o.35a400/ Lv d|=0.10223-f I. 14400 44. 0

r0- -0.3s5a11-1 +1.0a0s11 +10 2482 I +0 040100 1 7 4 1.. die-0.084694 1. 14400 44. 0

5 4* h in surfaces (An/r) difier by a maximum of 20.5% each L L are the lenses and the distances (d) of the individual surface apices ruware the radii difier by a maximum of 1:0.05-f each from the values d1 dm are the lens thicknesses and air spaces taken from the following numerical example.

tween the lenses, 5

Lenses Radfl Thicknesses and m o A n/r Separations r =+0.576526- 1.290489 L, l I a, =0.06956-f 1. 74400 44. 9 U n=+1.29999-f 0.572312/f +0 393732 1 11:09am. +1 693334/1 H= L da=0.10931-f 1. 66672 48. 4

n= 0.000000 L d4=0.01590-] 1. 62536 35. 6

n=+0.263151-f 2.376430/f d4=0.27726-f n=0.293143-f -2.4s4282/ L v d.=0.0198s- 1. 72825 26. 3

r1=-2.76746-j +0.263148If d1=0.00596-/ n=--2.13581-f -0.348346/f Lv.. lil=0.09600'f 1. 74400 44.9

n=-0.393732J +1.889610/f +21 6682 1 dFO'OHQB'I +0 034336 T10: Lvr d10=0.07155-f 1. 74400 44. 9 If rn=0.695123-/ +1.070314/j 72,; are the refractive indices, and wherein v are the Abbe numbers. LI L are the lenses 3. A photographic objective according to claim 1 charaware the radii acterized in that the individual powers of the refracting d1 are the thicknesses and air spaces surfaces (An/r) differ by a maximum of 1-0.5/f each 80 and the distances (d) of the individual surface apices differ by a maximum of 10.05 f each from the values taken from the following numerical example:

tween the lenses, fl are the refractive indices, and v are the Abbe numbers.

References Cited in the file of this patent UNITED STATES PATENTS Lenses Rndli Thicknesses and 11 a A 71/1 Separations ri=+0.577316-f +1.288722/f L d1=0.06778'[ 1. 74400 44. 9

rz=+1.31122-f --0.667410If d4=0.00311- n=+0.3914364 +1.703258/f Ln dr=0.10821-f 1. 66672 48. 4

r4=w 0.000000 Lm lil=0.01710'f 1 1.62536 35.6

d=0.28451'f n=0.293543-f -2.520925/f Lw d3=0.03109-f 1. 74000 28. 2

- r1=2.77122-f +0.267030/j d1=0.00994-f r =-2.078l1-f -0.36s01s// Lv di=0.08084-f 1. 74400 44. 9

n=0.388640-f +1.914368/f dn=0.00311-j I T10=+10.8747'f +0.06s416/j Lvx dm=0.08395-f 1. 74400 44 9 ru=0.711298-f +1.045975l/ wherein L L are the lenses, 55 r, r are the radii, 2,349,893 d d are the lens thicknesses and air spaces be- 2,735,340

tween the lenses, n are the refractive indices, and v are the Abbe numbers. 60 427,008

4. A photographic objective according to claim 1 characterized in that the individual powers of the refracting Warmisham et a1. May 30, 1944 Aklin Feb. 21, 1956 FOREIGN PATENTS Great Britain Apr. 12, 1935 Germany Sept. 27, 1938 Great Britain Dec. 10, 1952 

